Roll feed apparatus for intermittently feeding a workpiece

Abstract

A roll feed apparatus of the type including a pair of rolls for clamping a workpiece therebetween and for intermittently feeding the workpiece, comprises a differential gear, operatively connected to at least one of the rolls, for rotating the roll(s). A mechanical feeding mechanism is connected to the deferential gear for outputting a rotational output thereof to the differential gear for effecting the intermittent feeding. Fine adjustment of the intermittent feeding is effected by an adjustment arrangement which includes a servomotor, also connected to the differential gear, for outputting a rotational output thereof to the differential gear, a rotational angle sensor for sensing a rotational angle of the servomotor to output a rotational angle signal representing the rotational angle sensed, reference position providing element for providing a reference position signal representing a reference position of the workpiece, and servomotor controller for comparing the rotational angle signal with the reference position signal to produce a signal representing the difference therebetween for controlling the servomotor to correct the difference.

What is claimed is: 
     
       1. A roll feed apparatus of the type including a pair of rolls for clamping a workpiece therebetween and for intermittently feeding the workpiece, said apparatus comprising: a differential gear, operatively connected to at least one of the rolls, for rotating the at least one roll;   mechanical feeding means, including a cam indexing unit connected to said differential gear, for outputting a rotational output to said differential gear and for effecting a primary intermittent feeding of said workpiece; and   means for controlling said intermittent feeding effected by said cam indexing unit and providing fine adjustment of rotation of the rolls, said controlling means including:   a) an electrical driving means, also connected to the differential gear, for outputting a rotational output to the differential gear;   b) rotational angle sensing means for sensing a rotational angle of the electrical driving means to output a rotational angle signal representing the rotational angle sensed;   c) reference position providing means for providing a reference position signal representing a reference position of the workpiece; and   d) a control means for comparing the rotational angle signal with the reference position signal to produce a signal representing the difference therebetween and for controlling the electrical driving means to correct the difference;   whereby said mechanical feeding means allows stable and reliable primary intermittent feeding of the workpiece whereas said electrical driving means ensures fine adjustment of rotation of the rolls and correction of errors in feeding.   
     
     
       2. A roll feed as recited in claim 1, wherein the reference position providing means comprises a position sensor arranged at a travelling passage of the work piece to be fed by the rolls and wherein said cam indexing unit includes a casing, an input shaft and an output shaft mounted in said casing, a cam mounted for rotation about said input shaft and a cam follower mounted on said output shaft adapted to engage said cam. 
     
     
       3. A roll feed as recited in claim 1, further comprising rotational position sensing means for sensing a rotational position of the cam indexing unit to output a rotational position signal representing the rotation position, and wherein the control means compares the rotational angle signal with the rotational position signal and based on the comparison control the electrical driving means to synchronize it with the mechanical feeding means. 
     
     
       4. A roll feed apparatus of the type including a pair of rolls for clamping a workpiece therebetween and for intermittently feeding the workpiece, said apparatus comprising: a differential gear, operatively connected to at least one of the rolls, for rotating the at least one roll;   a mechanical feeding means, including a mechanical intermittent rotation mechanism, connected to the differential gear, for outputting a rotational output to the differential gear and for primary feeding of said workpiece;   an electrical driving means including:   a) a servomotor, also connected to the differential gear, for outputting a rotational output to the differential gear;   b) rotational angle sensing means for sensing a rotational angle of the servomotor to output a rotational angle signal representing the rotational angle sensed;   c) reference position providing means for providing a reference position signal representing a reference position of the workpiece; and   d) servomotor control means for comparing the rotational angle signal with the reference position signal to produce a signal representing the difference therebetween for controlling the servomotor to correct the difference;   whereby said mechanical feeding means allows stable and reliable primary intermittent feeding the workpiece whereas said electrical driving means ensures fine adjustment of rotation of the rolls and correction of errors in feeding.   
     
     
       5. A roll feed as recited in claim 4, wherein the reference position providing means comprises a position sensor arranged at a travelling passage of the workpiece to be fed by the rolls. 
     
     
       6. A roll feed as recited in claim 4, further comprising rotational position sensing means for sensing a rotational position signal representing the rotation position, and wherein the servomotor control means compares the rotational angle signal with the rotational position signal and based on this comparison controls the servomotor to synchronize it with the mechanical feeding means.